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This module is automatically imported during initialization. The automatic
import can be suppressed using the interpreter’s -S option.

Importing this module will append site-specific paths to the module search path
and add a few builtins, unless -S was used. In that case, this module
can be safely imported with no automatic modifications to the module search path
or additions to the builtins. To explicitly trigger the usual site-specific
additions, call the site.main() function.

Changed in version 3.3: Importing the module used to trigger paths manipulation even when using
-S.

It starts by constructing up to four directories from a head and a tail part.
For the head part, it uses sys.prefix and sys.exec_prefix; empty heads
are skipped. For the tail part, it uses the empty string and then
lib/site-packages (on Windows) or
lib/pythonX.Y/site-packages and then lib/site-python (on
Unix and Macintosh). For each of the distinct head-tail combinations, it sees
if it refers to an existing directory, and if so, adds it to sys.path and
also inspects the newly added path for configuration files.

If a file named “pyvenv.cfg” exists one directory above sys.executable,
sys.prefix and sys.exec_prefix are set to that directory and
it is also checked for site-packages and site-python (sys.base_prefix and
sys.base_exec_prefix will always be the “real” prefixes of the Python
installation). If “pyvenv.cfg” (a bootstrap configuration file) contains
the key “include-system-site-packages” set to anything other than “false”
(case-insensitive), the system-level prefixes will still also be
searched for site-packages; otherwise they won’t.

A path configuration file is a file whose name has the form name.pth
and exists in one of the four directories mentioned above; its contents are
additional items (one per line) to be added to sys.path. Non-existing items
are never added to sys.path, and no check is made that the item refers to a
directory rather than a file. No item is added to sys.path more than
once. Blank lines and lines beginning with # are skipped. Lines starting
with import (followed by space or tab) are executed.

For example, suppose sys.prefix and sys.exec_prefix are set to
/usr/local. The Python X.Y library is then installed in
/usr/local/lib/pythonX.Y. Suppose this has
a subdirectory /usr/local/lib/pythonX.Y/site-packages with three
subsubdirectories, foo, bar and spam, and two path
configuration files, foo.pth and bar.pth. Assume
foo.pth contains the following:

# foo package configuration
foo
bar
bletch

and bar.pth contains:

# bar package configuration
bar

Then the following version-specific directories are added to
sys.path, in this order:

Note that bletch is omitted because it doesn’t exist; the bar
directory precedes the foo directory because bar.pth comes
alphabetically before foo.pth; and spam is omitted because it is
not mentioned in either path configuration file.

After these path manipulations, an attempt is made to import a module named
sitecustomize, which can perform arbitrary site-specific customizations.
It is typically created by a system administrator in the site-packages
directory. If this import fails with an ImportError exception, it is
silently ignored.

After this, an attempt is made to import a module named usercustomize,
which can perform arbitrary user-specific customizations, if
ENABLE_USER_SITE is true. This file is intended to be created in the
user site-packages directory (see below), which is part of sys.path unless
disabled by -s. An ImportError will be silently ignored.

Note that for some non-Unix systems, sys.prefix and sys.exec_prefix are
empty, and the path manipulations are skipped; however the import of
sitecustomize and usercustomize is still attempted.

Flag showing the status of the user site-packages directory. True means
that it is enabled and was added to sys.path. False means that it
was disabled by user request (with -s or
PYTHONNOUSERSITE). None means it was disabled for security
reasons (mismatch between user or group id and effective id) or by an
administrator.

Path to the user site-packages for the running Python. Can be None if
getusersitepackages() hasn’t been called yet. Default value is
~/.local/lib/pythonX.Y/site-packages for UNIX and non-framework Mac
OS X builds, ~/Library/Python/X.Y/lib/python/site-packages for Mac
framework builds, and %APPDATA%\Python\PythonXY\site-packages
on Windows. This directory is a site directory, which means that
.pth files in it will be processed.

Path to the base directory for the user site-packages. Can be None if
getuserbase() hasn’t been called yet. Default value is
~/.local for UNIX and Mac OS X non-framework builds,
~/Library/Python/X.Y for Mac framework builds, and
%APPDATA%\Python for Windows. This value is used by Distutils to
compute the installation directories for scripts, data files, Python modules,
etc. for the user installation scheme.
See also PYTHONUSERBASE.

Adds all the standard site-specific directories to the module search
path. This function is called automatically when this module is imported,
unless the python interpreter was started with the -S
flag.

Changed in version 3.3: This function used to be called unconditionnally.

If it is called without arguments, it will print the contents of
sys.path on the standard output, followed by the value of
USER_BASE and whether the directory exists, then the same thing for
USER_SITE, and finally the value of ENABLE_USER_SITE.

If both options are given, user base and user site will be printed (always in
this order), separated by os.pathsep.

If any option is given, the script will exit with one of these values: O if
the user site-packages directory is enabled, 1 if it was disabled by the
user, 2 if it is disabled for security reasons or by an administrator, and a
value greater than 2 if there is an error.